Motorcycles are commonly provided with tandem seats, which enable the motorcycle to carry a passenger in addition to the driver of the motorcycle. It is often desirable to include a backrest at the rear of the tandem seat for both the comfort and safety of the passenger. However, the backrest can be an aesthetic and practical hindrance when the motorcycle is not carrying a passenger. Accordingly, a number of backrests for tandem seats have been developed which fold up when not in use and fold out during use. Representative backrests are disclosed in U.S. Pat. Nos. 4,953,911 and 4,679,647. The present invention recognizes a need for an alternate more effective configuration of a tandem seat for a motorcycle which has a backrest convertible between a fold-up position of nonuse and a fold-out position of use. Accordingly, it is an object of the present invention to provide such a tandem seat for a motorcycle. More particularly, it is an object of the present invention to provide a tandem seat for a motorcycle having a convertible backrest which is concealed when not in use. These objects and others are accomplished in accordance with the invention described hereafter.